It is well known to equip the casings of electrical motorised reduction gear units, for driving windshield wipers for motor vehicles, with a brush carrier plate. Such a brush carrier plate is typically made of a plastics material, and has a circular central aperture through which the collector or commutator of the motor of the reduction gear unit passes. The carrier plate is generally equipped with two or three carbon brushes which are arranged in guides incorporated in the carrier plate.
The brush carrier plate also includes various electrical components which form part of the power supply circuit for the drive unit. Such a component consists for example of a connecting terminal for bringing the power supply into the drive unit, and/or a thermal protection component, that is to say a device which is arranged to interrupt the electrical supply to the drive unit in the event of overheating of the latter,
In general, the brush carrier plate is mounted on the body of the drive unit, being engaged on suitable dampers. During operation of the motorised reduction gear or drive unit, the armature of the motor of the latter has a tendency to vibrate, and the carbon brushes which are in engagement with the commutator, carried by the rotor that constitutes the armature, transmit these vibrations to the carrier plate. Since the above mentioned electrical components are carried by the latter, this vibration is therefore transmitted to those components themselves. This gives rise to noises and to perturbations in the power supply circuit to the drive unit.